The invention relates to a wheel for a motor vehicle, and more particularly to a wheel having a plurality of spokes defining relatively large air openings therebetween, each of the spokes comprising of ribs extending essentially radially from the wheel hub to the wheel rim.
This application claims the priority of German Patent Application No. 196 12 115.9 filed on Mar. 27, 1996 in Germany, the disclosure of which is expressly incorporated by reference herein.
A wheel for a motor vehicle is known from German Design Patent M 95 03 760, said wheel having spokes between air openings, said spokes each consisting of two outer ribs running radially and extending from the rim flange to the wheel hub, with a continuous elongate air opening provided between the outer ribs.
A goal of the invention is to provide a wheel for a motor vehicle having a wheel spider which provides optimum air throughput and guarantees high strength.
These and other goals have been achieved according to the present invention by providing a wheel for a motor vehicle including a wheel spider having a plurality of spokes extending radially between a wheel hub and a wheel rim, adjacent ones of the spokes and the wheel rim defining air openings therebetween, each of the spokes comprising: at least two outer ribs which extend approximately parallel to each other between the wheel hub and the wheel rim; and at least two inner ribs extending diagonally between the outer ribs, the inner ribs intersecting each other.
These and other goals have also been achieved according to the present invention by providing a mold for a wheel for a motor vehicle, the mold comprising mold openings for receiving a material for forming the wheel, the mold openings defining a wheel hub, a wheel rim, and a plurality of spokes extending radially between the wheel hub and the wheel rim, the mold openings which define each of the spokes including mold openings which define: at least two outer ribs which extend approximately parallel to each other between the wheel hub and the wheel rim; and at least two inner ribs extending diagonally between the outer ribs, the inner ribs intersecting each other.
One advantageous feature achieved by the present invention results from the construction of the wheel spider with a plurality of spokes that join to form a lattice-like composite structure for strength. For this purpose, inner ribs are provided which run diagonally between the outer ribs of each spoke, said inner ribs intersecting with one another. The inner ribs intersect each other in an area between the wheel center point and the wheel rim, for example between 30% and 70% of the radial distance between the wheel center point and the wheel rim, and more preferably between 50% and 70% of the radial distance between the wheel center point and the wheel rim. In one preferred embodiment, five spokes are provided, which achieves a particularly strong wheel structure.
The filigree (i.e., lattice-like) design of the individual spokes with additional internal air openings in each spoke between the outer ribs and the internal ribs advantageously achieves a stable wheel with great strength, especially high torsional stiffness. This is accomplished in particular since the outer ribs of adjacent spokes which are directly opposite each other in a circumferential direction (i.e., the outer ribs of adjacent spokes which define one of the relatively large air openings in the wheel), as well as one diagonal inner rib of each spoke, meet at a node proxima a hole for a mounting bolt. In one preferred embodiment, four internal air openings are provided in each spoke, which achieves a particularly strong wheel structure.
In addition to the relatively large air opening between the individual ribs, smaller air openings are provided within the spokes that are made roughly polygonal, e.g. triangular. The diagonal position of the inner ribs means that in each case two air openings of approximately the same size are located opposite one another with respect to the intersection point between the inner ribs.
The relatively large air openings defined between adjacent spokes of the wheel are essentially triangular and have at their radially outer periphery with respect to the wheel hub an external curved shape determined by the wheel rim. The relatively large air openings are rounded at the vertices of the outer ribs of adjacent spokes, with these rounded areas being located opposite the holes for the mounting bolts, respectively.